Total knee replacement prostheses of the condylar type comprise a femoral component, a tibial base plate and a plastics meniscal component arranged to support the femoral component, and to be mobile to a limited extent on the base plate. One typical prosthesis of this kind is described in UK Patent Application No. 2280375. Accurate and rapid fitting of orthopaedic implants is facilitated by the use of suitable instruments so that the prosthesis, when installed, operates in the way in which it is designed.
It is an important consideration in fitting a knee prosthesis that the tibial base plate should be fixed on the strongest portion of resected bone, should not twist within the bone and that, when fixed, the joint should articulate in the most effective manner.